Gring: Mixed longitudes result in clockwise WKT string

When given longitudes of mixed sign (specifically when crossing the Prime Meridian), Gring outputs a clockwise WKT string.

Test WKT string lons mixed.................................FAILED
     Expected: POLYGON((-2.00 0.00, -1.00 0.00, 1.00 2.00, 0.00 2.00, -2.00 0.00))
     Got:      POLYGON((0.00000 2.00000, 1.00000 2.00000, -1.00000 0.00000, -2.00000 0.00000, 0.00000 2.00000))

Note that mixed latitudes seem to be fine:

Test WKT string lats mixed.................................FAILED
     Expected: POLYGON((0.00 -2.00, 0.00 -1.00, 2.00 1.00, 2.00 0.00, 0.00 -2.00))
     Got:      POLYGON((2.00000 0.00000, 2.00000 1.00000, 0.00000 -1.00000, 0.00000 -2.00000, 2.00000 0.00000))